Effects of temperature, hypoxia and activity on the metabolism of juvenile Atlantic cod

INTRODUCTION The oxygen consumption (M O 2 ) of fish can be separated into standard, routine and active metabolic rate (Fry, 1971). The standard metabolic rate (SMR) corresponds to the minimum maintenance metabolism of a resting fish in a post absorptive state. The routine metabolic rate describes a fish that is feeding, growing, producing sexual products or any other activities that elevate the standard metabolic rate. Active metabolic rate (AMR) is the metabolic rate measured during swimming at maximum sustained speed (Fry, 1971; Brett 1972; Brett & Groves, 1979). In some cases M O 2 can be higher than AMR, if for example fish are forced to swim at speeds exceeding the maximum sustainable swimming speed for a limited period of time. This is termed the maximum metabolic rate (MMR) (Bushnell et al. 1994). The M O 2 of resting, post-absorptive fish depends among other things on temperature and ambient water oxygen availability. In the aquatic environment, fluctuations in the oxyge